Friday, August 27, 2010

The Scientific American blog has a short piece on how stone tools have been an integral part of human evolution for the past 3.4 million years. It's mostly a series of links to some articles featured on the online features of the magazine, but it's accompanied by this nifty video of Kyle Brown knapping:

Clearly, someone's very impressed at 1:58, when he knocks off a big honking flake! All kidding aside, I always enjoy videos like this, that really focus on the piece being knapped and zoom appropriately. They really do a wonderful job of showing the hand-eye coordination involved in flintknapping, as well as how much slight hand motion, control and feeling around is involved in the act... it's not just randomly bashing rocks, folks! And though Brown doesn't use gloves or anything to protect his hands in this demo (though notice the pad on his legs), for any novice knapper reading this, remember, in lithics as in love, use protection!

Thursday, August 26, 2010

A couple of days ago, I mentioned how excavations at a Paleoindian site in Utah has revealed that the site's occupants had been milling various seeds to produce different kinds of flours. In that post, I mentioned how this discovery re-emphasized the fact that hunter-gatherers in general hunt as well as gather. In fact, outside of the highest latitudes, plant foods often account for a majority of the caloric intake of ethnographically-documented forager groups, suggesting that this was also very likely the case in prehistory. This is an especially important realization for Paleoindian research, since public (and sometimes even academic) perception is that Clovis and Folsom foragers were essentially big guys with big spears killing big things, i.e., megafauna. Estbalishing that they were not only collecting plants but also processing some of them rather intensively (grinding is a very time-consuming activity, and so is the shaping of grinding implements) reinforces recent research that suggests that Paleoindian diets were as a whole much more diverse than is generally believed (Hill 2008).

Grinding plant matter into flour also has important other implications about the structure of hunter-gatherer subsistence and social life, however. To understand these, it's helpful to look at some of the earliest traces of flour production in the archaeological record, one example of which is provided by the Gravettian site of Bilancino, in Tuscany, Italy, which dates to about 25,000BP uncal. (Aranguren et al. 2007), and which I mentioned briefly earlier. Bilancino is a very interesting site: because of preservation issues, namely the acidic nature of the sediment there, no bone was preserved at all. This has forced the investigators to thoroughly investigate other kinds of archaeological remains that are not usually the focus of such intensive scrutiny in many Paleolithic studies. This includes notably charcoal, pollen and starch grain recovered from the surface of a grindstone. These efforts have paid off in spades by revealing that the occupants of Bilancino had been grinding cattail (Typha latifolia), likely its roots, as well as wild grasses to produce flour.

Aranguren et al. (2007) explicitly discuss the potential impact of flour on Paleolithic lifeways. They specificallyhighlight that it "implies the availability of an elaborate product, a flour, with high energy content, that is rich in carbohydrates, easily storable and transportable, to make a kind of bread (biscuits) or a porridge" (Aranguren 2007: 853). This means that plant material could be preserved and stored for much longer periods of time, which effectively can provide carbs during seasons such as winter during which they are normally difficult if not impossible to obtain. Also, it provides a subsistence items that serves as a buffer against the fluctuating availability of other types of subsitence resources, such as animal tissue. Lastly, because flour is easily ingested and digested, it also provides a foodstuff that both very young and very old members of a group can consume - and maybe even produce while adults are off procuring other things. This means that survival to adulthood and into old age can be facilitated, which has the potential of significantly reorganizing the way labor is divided within a society, and increasing the generational knowledge available to given forager groups.

A few items of note, not all paleo-related, that grabbed my attention over the past couple of days:

There's an intriguing report at Slate about the lone survivor of an 'uncontacted' (a term I abhor) native tribe in Brazil that was decimated by ranchers and loggers. The man now live in almost complete isolation in a 31-squared-mile 'safe zone' monitored by government official.The report includes an interesting allusion to ethnoarchaeological observations on a series of huts that allowed officials to estimate the size of hiss original tribe and pinpoint the year, 1996, they were eradicated by land-settler. Chilling.

Gizmodo offers an interview with Timothy Taylor who discusses some aspects of his upcoming book The Artificial Ape: How Technology Changed the Course of Human Evolution. The beginning of the exchange is wrapped in one of those annoying "Darwin was wrong" tropes that is completely misleading, but the rest of the piece presents an good overview of Taylor's view that human tool-use is radically different than any behavior observed in other animals. I should have more to say about this soon.

BYU archaeologist Joel Janetski and his team have found evidence that prehistoric foragers ground seeds and plants into flour some 10,000 years ago at North Creek Shelter, in Utah. The milled seeds include sage, salt bush and various grasses, which were processed on grindstones. The discovery provides evidence that Paleoindian diet may have been more varied than generally acknowledged by those who focus on the 'hunter' in 'hunter-gatherer'.

At Neuroanthropology, Greg Downey provides a long but very interesting discussion of Pat Shipman's new paper on the human-animal connection, focusing especially on the dog-human connection in human evolution.

Monday, August 23, 2010

In a recent paper, O. Moro Abadia and M.R. Gonzales Morales (2010) argue that an important component of the 'multiple species model' (MSM) that sees Neanderthals as having essentially 'modern' behavioral capacities and that originated in the late 90's is based not so much on new discoveries as it is on new ways of looking at the archaeological record. Specifically, they make the case that part of why Neanderthals have become associated with artistic capacity signaling 'modern' behavior is a growing awareness over the past 30 years or so of the fact that personal ornaments and mobiliary (i.e., portable) art such as statuettes and engraved pieces are intrinsically symbolic in nature. This has resulted in what they claim is a paradigmatic shift away from considering cave art as the sole diagnostic of developed artistic (and by extension symbolic) capacities, to one that sees ornaments and mobiliary art as fundamental markers of that capacity. In turn, the association of Neanderthals with ornaments - based especially on Chatelperronian assemblages from Arcy-sur-Cure and Quincay - has likewise shifted the general perception of them towards a more 'human' prehistoric hominin over the past generation.

This is an interesting paper that makes some worthwhile points and provides some good food for thought. First, even though the idea of a Neanderthal authorship of the Chatelperronian has recently come under fire, the fact that pierced shells and coloring material have been found in even older Mousterian contexts renders moot the question of whether Neanderthals had the capacity to use and produce such technology in the absence of H. sapiens stimulus. Second, it's noteworthy that recent claims (i.e., in the past decade) about the much greater time depth of archaeologically visible traces of symbolic behavior in Africa are all based on this kind of evidence (e.g., engraved ochre at Blombos, early ochre use at PP13 and other sites, pierced shells in South and North Africa, etc.). In fact, prior to what Moro Abadia and Gonzales Morales consider the 'reconceptualization' of Paleolithic art, it was widely agreed that the Middle Stone Age and the Middle Paleolithic were very similar.

To their analysis, I would only add observations about two other aspects of the fundamental impact of considering ornaments as reflective of artistic and symbolic behavior. First, part of why personal ornaments and ochre became the focus of so much attention beginning in the 80's was that they were argued by people like Randy White to characterize the Aurignacian, in contrast to the Mousterian which lacked them (White 1992, 2006). This was in part driven by the observation that Paleolithic cave art was essentially absent from the Aurignacian record even though that technocomplex was argued to be the expression of the arrival of symbolically-enhanced modern humans in Europe. Even if one includes the Fumane and Chauvet art, we're hardly talking about a very abundant record, especially compared to later periods of the Paleolithic. Therefore, rightfully broadening the definition of 'art' to include personal ornaments at first distinguished Neanderthals from modern humans, though that kind of evidence soon made it clear that Neanderthals also were symbolic beings, at least to an extent. In an unexpected twist, though, this reconceptualization of what is 'art' combined to a renewed interest in the MSA record during the 2000's ultimately ended up establishing that artistic behavior was a integral component of the behavior of at least some modern human groups much earlier than for Neanderthals as a whole.

My second observation is about the durability of ornaments. Ornaments are more resilient than cave art, since they don't need the exceptional preservation conditions of the latter to preserve in the archaeological record. If bones are present in a Paleolithic deposits, odds are that any associated ornaments made of, say, ivory, will also preserve, unlike most cave art which requires unusually stable temperature and humidity to preserve longer than a few hundred years. By extension, considering ornaments 'art' means that, on purely probabilistic grounds, the first expressions of symbolic behavior would be traced back much further in time than if only identified on the basis of parietal art. The recent discoveries in Africa pushing ornament use to about 82kya clearly underscore the underappreciated importance of their sheer relative durability although, unlike for parietal art, human agency in perforating these early shells needs to be demonstrated rather than assumed.

Clearly, then, the authors are right in emphasizing the impact on paleoanthropological research of redefining Paleolithic artistic behavior to include personal ornaments (and portable art more broadly). This is true for an even wider range of reasons than even they discuss. I like this snippet of their concluding paragraph, which I think neatly sums up one of their fundamental points:

"While some specialists have a tendency to believe that science develops through the accumulation of discoveries and inventions, the MSM illustrates how scientific research is also influenced by theoretical paradigms that generate and sustain knowledge, determining the questions that are asked and those that are excluded. The latter statement does not imply that science is exclusively driven by conceptual propositions. Rather, we suggest that conceptual, technical and factual developments are interlinked... We have focused upon the theoretical dimension of the new discourses about Neanderthals and art to argue that scientific developments are not part of an ever-growing piecemeal process, but one influenced by a set of factual discoveries, previous knowledge, current beliefs and disciplinary paradigms."

The 2010 Stone Age Fair will be held in Loveland, CO, on Sept. 25 and 26. Although I wasn't planning on going, in the end, I was able to make it to last year's 75th edition, and it was a lot of fun and a great way to learn about Paleoindian archaeology and Colorado archaeology generally. I'm definitely planning to attend this year's Fair, which also will include the following two presentations:

Building a Paleoindian Research Program in Southeastern Idaho & Northern UtahBonnie Pitblado

For historical reasons, virtually nothing is known about the Paleoindian record of southeastern Idaho and northern Utah. However, in this region, four major physiographic zones converge—the Central Rockies, Great Basin, Columbia Plateau, and Wyoming Basin—creating an exceptionally diverse and inviting environment. Four years of foundational fieldwork has begun to reveal that the Paleoindian record of the region, like its environment, is diverse…and very inviting!

Excavations at Barger Gulch Locality B in Middle Park Colorado have produced a rich assemblage of Folsom artifacts occurring within clusters associated with hearth features. Large scale excavations at the site over a 10 year period have allowed us to identify a number of aspects of Folsom spatial and social behavior.

Regular AVRPI readers might remember that some of Surovell's research on the effectiveness of wooden vs. stone projectile point tips was discussed earlier on this blog (and featured on Mythbusters!). In addition to the talks, there will be artifact displays, and the great Bob Patten (who was kind enough to come show Lithic Analysis students how to knap this past srping) will be doing a flintknapping demo, while Bob Heid will be making beads. Find out all the details about this year's Stone Age Fair, including directions and a schedule of event, by visitng their website.

Friday, August 20, 2010

The Chatelperronian is a lithic industry that springs up for several thousand years during the transition from Middle to Upper Paleolithic industries. Its precise age is debated, but it clearly is associated with this interval. One of the reasons the Chatelperronian is the subject of so much debate is because, since the discovery of a Neanderthal in a Chatelperronian level at the site of
St. Césaire in 1978, it has widely been believed that Neandertals were the makers of this industry. This is important because up to that point, the Chatelperronian had been considered a true 'Upper Paleolithic' culture. Since the Upper Paleolithic had been thought to correspond to the arrival of modern Homo sapiens in Europe, the St. Cesaire discovery - and the association of Neanderthals with the Upper Paleolithic - meant that this association needed to be rethought. This has led to two main perspectives: those who see the Chatelperronian as an independent development by Neanderthals (d'Errico et al. 1998), and those who see the Chatelperronian as the result of the acculturation of Neanderthals by modern humans (Mellars 2005). The key thing here is that, in spite of much acrimonious debate between the two perspectives, both fundamentally attribute the Chatelperronian (and other coeval 'transitional' industries like the Uluzzian and Szeletian) to Neanderthals.

This may be about to change. In a short paper in press in the Journal of Human Evolution, Bar-Yosef and Bordes (2010) question this fundamental association in light of a revision of the two sites on the Neanderthal-Chatelperronian association is based: Grotte du Renne at Arcy-sur-Cure, and St. Césaire at La Roche à Pierrot, both in France. At Grotte du Renne, the authors suggest that the Neanderthal remains were incorporated into Chatelperronian deposits as a result of that layer's occupants digging into the Mousterian layer when they first settled into the cave. Thus, the Neanderthal bits would come from the Mousterian levels below. To them, such mixing is indicated by 1) the position of the remains (near the cave mouth) where dug up dirt would have been dumped, 2) the presence of a dug hearth indicating digging did take place, 3) a decrease in the number of teeth from the bottom to the top of the Chatelperronian levels, and 4) dicrepancies between radiocarbon dates and the stratigraphy of the late Mousterian and Chatelperronian layers.I think this is a fair argument, especially considering that the site was excavated prior to the establishment of the complete excavation methods used today, as the authors also underline.

At St. Césaire, where the the secondary burial of a Neanderhal was found in the Chatelperronian, Bar-Yosef and Bordes argue that the presence of distinct 'Mousterian' and 'Chatelperronian' components of the lithic industry and the fact that not all artifacts show a similar state of preservation suggest caution is needed before we can accept that it was not a mix of Mousterian and Chatelperronian levels. Because the burial is found in the upper (of two) Chatelperronian level, they argue that it was probably not deposited by occupants of the site anyway, implying that Neanderthals who did not make Chatelperronian tools might have buried one of their deceased at St. Césaire, perhaps in an effort to mark the site as theirs following the arrival of whoever made the Chatelperronian.

In my view, Bar-Yosef and Bordes' case is much stronger for Grotte du Renne than it is for St. Césaire, especially since bone refitting at St. Césaire has recently demonstrated that mixing between the Mousterian and the Chatelperronain was a negligible occurrence at the site (Morin et al. 2005). The need to invoke an explanation that doens't depend strictly on stratigraphic of artifactual data also weakens their overall argument. I say this because if their argument is followed to its logical end, it would mean that, even if you found that unheard of goody that would be a site containing only Chatelperronian layers and thus could exclude stratigrpahic mixing as an explanation, the presence of Neanderthal remains (or at least of a secondary Neanderthal burial) could still be explained away as a result of self-affirming Neanderthals claiming a stake to a given bit of territory. That's not to say that it's impossible, of course, and I will concede that the St. Césaire burial is the only relatively undisputed case of a Neanderthal secondary burial, so the practice was never common and who knows what it really might have meant, as the authors concede. Given that this is the case, though, you wouldn't expect a very unusual behavior to be the preferred manner in which Neanderthals would have marked their territories in the context of encounters with new groups of hominins.

In any case, Bar-Yosef and Bordes raise the specter that Neanderthals may not have been the makers of the Chatelperronian. They're circumspect in their conclusions of what this might mean, suggesting that archaeologists "should therefore start afresh, testing hypotheses about the hominins responsible for the formation of Chatelperronian contexts" rather than assume anything about their makers based on the potential unfounded assumption that they were Neanderthals. This is a view that I have a lot of sympathy for, having myself argued for the need for a similar perspective when interpreting the Uluzzian 'transitional' industry of southern Italy (Riel-Salvatore 2009, 2010 - go ahead, treat yourself and click, you'll find free pdfs). Ultimately, though, the revision proposed by Bar-Yosef and Bordes needs to be taken cautiously, especially as it concerns the St. Cesaire remains. One thing it doesn't do is associate the Chatelperronian with modern humans, though that's certainly one of the possible correlates of their paper, especially when they rail against 'continuity models' of human evolution in their conclusion. That said, if this revision and others like it have the beneficial result of getting people to carefully excavate and document new sites bearing 'transitional' assembalge, I'm all for them!

References:

Bar-Yosef, O., & Bordes, J.G. (2010). Who were the makers of the Châtelperronian culture? Journal of Human Evolution DOI: 10.1016/j.jhevol.2010.06.009

Thursday, August 19, 2010

While everybody was busy talking about unexpectedly old cutmarks and other Pleistocene goings-on last week, the paper by Strasser et al. (2010) describing the discovery of quartz handaxe assemblages on Crete quietly came out in Hesperia. This is a topic that was discussed at length on this blog, in severalposts that generated a large amount of comments a few months back. The sticking point of all the arguments concerned the chronology of the handaxes, so without further ado, here's the money quote (Strasser et al. 2010: 185-186):

"The dating of the Palaeolithic in the Plakias region presents a considerable challenge, not least because of the long period of time that may have elapsed since the occupation of the earliest sites, during which postdepositional natural processes may have obscured the archaeological record. Additionally complicating the issue are the small number of sites, the lack of excavation, and the impact of modern development on the area, which has destroyed many sites.

Several approaches to dating were attempted, and our research on this topic continues. At Preveli 2, east of the Preveli Gorge, Palaeolithic artifacts are associated with a flight of marine terraces resulting from relatively high sea levels in the Pleistocene that were preserved by subsequent rock uplift. The lowest late Pleistocene marine terraces resulting from high stands of the sea at Preveli (14 ± 1 masl) and Schinaria (21 ± 1 masl) have 2-sigma calibrated radiocarbon ages of 45,400 ± 1,600 and 49,120 ± 2,890 years b.p., respectively, and are correlated with Marine Isotope Stages 3.3 and 3.4, both eustatic high stands. The higher terraces, at 59 and 96 masl, are unquestionably older. How much older? Assuming similar rates of rock uplift (1.4 ± 0.1 m/kyr) determined from the age-elevation relationships of the dated terraces at 14 and 21 masl, it is possible to estimate the approximate ages of the terraces associated with artifacts. This correlation provides an approximate age for the lithic artifacts. The higher terrace, at 96 masl, may belong to Marine Isotope Stage 5, possibly early 5e, ca. 110,000 b.p. Artifacts associated with the terrace at 59 masl could correlate with Marine Isotope Stage 5a, ca. 70,000 b.p. It should be stressed that these are rough approximations and these ages are probably minima that represent a terminus ante quem. If the uplift rate is changed, the terraces and the artifacts associated with them could be much older.

At Preveli 3, Preveli 7, Timeos Stavros 1, and Schinaria 5, Palaeolithic artifacts were found in outcrops of paleosols that exhibit the characteristics of the oldest maturity stage for such features, that is, Maturity Stage 6, or in geological terms, Marine Isotope Stage 6. Together these observations suggest an age of ca. 190,000–130,000 b.p. and serve as a terminus ante quem for the artifacts embedded within them. The stone tools were incorporated in the paleosols as part of a process described by Runnels and van Andel in Epirus: “the top of the Bt horizon itself would move gradually upward as a result of slow deposition, so engulfing any artifacts laid down on former land surfaces above it.” In other words, the Bt horizon, especially as much of the clay comes from eolian sources, will increase in thickness through time, slowly
engulfing clasts, such as stone tools, that were formerly in the A horizon.

In sum, the dating of the Palaeolithic sites is based on geological data derived from the study of marine terraces on the southwestern coast of Crete and our identification of paleosols, and these data place the Palaeolithic lithic artifacts firmly in the Pleistocene, ca. 130,000 b.p. or earlier. The chronology can be further refined, however, and a dating program
currently in progress may provide data for doing so." (references excised)

So, bottom line, the dating is largely indirect, but grounded by dated references points that provide a minimum age for the terraces where the handaxes were recovered. Interestingly, this indicates that these tools are, at most, 130,000 years old. Given that there do not appear to be more recent Paleolithic age (the rest of the implements reported in the paper are Mesolithic in age and techno-typology, which is an important discovery in and of itself), this implies that on current evidence, Crete was not occupied during the Late Pleistocene (ca. 130,000-10,000 BP). Why this was the case (and how an early colonization took place) is an interesting question that will need to be answered by future research.

In the meantime, here are a few take-away observations from the Strasser et al. (2010) report. First, on the basis of the drawing of the handaxes, these implements do appear to be human-made. Second, they are not isolated occurrences: the authors identified nine localities where these quartz tools were found, only three of which also yielded Mesolithic tools. This leaves open the possibility that the 'Paleolithic' sites represent task-specific components of the Mesolithic toolkit on Crete, but this is unlikely based on the association of handaxes with some of the terrace deposits described in the quote above. Third, as the authors indicate, this was not a case of a H. heidelbergensis (or a couple of them) washing onto Crete: the fact that nine sites (defined by the presence of a minimum of 20 stone tools) were found in a relatively small area indicates a somewhat sustained human presence on the southern coast of Crete. This does suggest that people got there purposefully (i.e., using some kind of watercraft), which leaves open the question of why Middle and Upper Paleolithic assemblages haven't (yet?) been found in the region or elsewhere on Crete (or any other large Mediterranean island, for that matter).

As a parting observation: one aspect of the discovery that definitely wasn't stressed in the media reports about these finds is how they were made. They were breathlessly reported as 'discovered' without much context. The authors actually set out to look for Mesolithic sites in southern Crete using a model developed for the Greek mainland that identified certain areas as having been most appealing for Mesolithic foragers. In other words, this wasn't a blind search for early stuff or simply a fortuitous discovery. Rather, it came about as the result of an explicit research design targeting some very specific questions. Good to see more of that in Paleolithic archaeology.

Mamma mia! Would you believe it's the 99th time we light this old four stone hearth to come together and rap about all things blog-ological anthropologica! I tried to shake things up a bit and diversify the offerings for this edition, to put a bit more emphasis on things non-archaeological/paleoanthropological, so without further ado, pull up a log,pour yourself a nice drink and enjoy!

Shifting to matters linguistic, let me point you to posts by Steve Chrisomalis about the origins of the word chairperson and its socio-historical context, and by Ben Zimmer about recent research on the endangered Inuit language Inuktun. Glen at Paleoglot also looks at origins in a post on the word kinnor while Jonathan Jarrett takes a critical look at recent claims that spoken Pictish has finally been decoded.

Turning to archaeology, Magnus Reuterdahl reports on his experience at the Swedish National Heritage board’s course on historic landscapes while Martin Rundkvist picks apart a recent study that tries to link the myth of Phaeton to an actual meteor crash in Antiquity. Speaking of taking apart, you should also definitely look at Chris Carl Feagans' very good smackdown of recent claims about having found the remains of John the Baptist that have lately come out of Bulgaria. Jumping west a continent and landing in the US Southwest, the Gambler's House presents a discussion on the dental evidence for agriculture. And if you want a glimpse of what life in the field is like for a Mediterranean archaeologist, then by all means check out Colleen Morgan's series of posts from her field projects in Greece and Jordan.

Greg Laden provides an interesting discussion of how "persistent ethnic differences in test performance may be entirely an artifact of the method used to 'adjust' the test." Switching gears somewhat, Bonn Aure provides a discussion on Visayan sorcery and witchcraft. And to touch on the news of the week re: the brouhaha about the Cordoba Center in NYC, Savage Minds has a pieces on the semiotics of islamophobia. And if you haven't read it yet, check out Krys D'Costa at her new digs at Scientopia and her wonderful threepostseries on coffee, a much loved topic here at AVRPI.

Alright, I'm already late putting this up (my apologies!), so that wrap's up the 99th edition of FSH. Installment #100 will be hosted over at Aardvarchaeology, so contact Martin if you want to submit a post!

Tuesday, August 17, 2010

AVRPI will be hosting the 99th edition of the Four Stone Hearth anthropology blog carnival tomorrow. Consider this a call for last-minute contributions: all branches of anthro are most welcome! Contact me if you have a post to submit or want to suggest interesting anthro posts you've seen around the web.

Monday, August 16, 2010

Well, at least the butcher, if not the tool-maker... McPherron et al. (2010) report the discovery of four bone fragments bearing marks left by stone tools from the the Dikika-55 locality in Ethiopia (dating to between 3.24-3.42 million years BP), a stone's throw from where the juvenile Australopithecus afarensis dubbed Selam was found. This is a pretty monumental discovery, in that it pushes back the evidence for the use of stone tool technology by about 800,000 years, and associates it fairly convincingly with A. afarensis (or, at least, as convincingly as can be done for those time frames). John Hawks and Greg Laden have interesting posts on some of the more salient aspects of the paper, which you should read if you're interested in this.

In a nutshell, McPherron and colleagues analyzed the bones using secondary electron imaging (SEI) and energy dispersive X-ray (EDX) to establish that the marks were, in fact, made in deep time before the bones fossilized. Having determined this, they then examined the morphology of the marks on the bone using ESEM (environmental scanning electron microscopy) and optical microscopes to establish that it was most similar to those of experimentally replicated marks made with stone tools used to cut flesh off a bone and crack bones open. I've looked at my share of cut marks over the years, and like Greg, I also agree with the authors that the DIK-55 cut marks look like marks made by stone tools. You'd have to never have looked at cut marks to argue with a straight face that the marks on the DIK-55 specimens look more like croc tooth marks than cut marks.

Given that the marks really seem to be genuine stone tool cut and percussion marks, the question then becomes one of establishing the age of the mark-bearing bones. As Hawks underlines, we're dealing with only four bones here, out of an unspecified total sample. So, we don't really know how common they were at DIK-55, since they do not meet the criteria usually used for collection - basically, they were collected because field observations suggested they might bear cut marks. And as Laden mentions, it'd be better if the bones in question had been collected in primary context, as opposed to from the surface next to their associated depositional context. This is important because there's always the possibility that they might have washed in or been somehow transported from another, potentially younger locality. That said, based on the absence of adhering sediment and the location of the specimens, their most likely provenience is from a sandy formation with a minimum age of 3.24 million years and a maximum age of 3.42 million years. The sample size issue is an interesting one to consider, but really, in this case the noteworthy feature of these bones is that they bear unambiguous traces of modification with stone tools, so their proportional importance is somewhat secondary.

OK, so, we have bones bearing marks made by stone tools that are older by some 800ky than the earliest known stone tool assemblages, which date to about 2.6-2.5mya (Semaw et al. 1997). What does it mean? Well, the most obvious conclusion is that the use of stone tools must be quite a bit older than has generally been assumed, and since A. afarensis is the only hominin associated with deposits that age in the region, they are the best candidates for having used them.

Here's the rub, though: there are no stone tools at DIK-55. Furthermore, the closest source of rocks that could have been used as stone tools is about 6km away. What does that mean? It means that, if A. afarensis really did use stone implements to process these remains, they must have brought them from a little ways away. That, in and of itself, is not earth shattering an observation. Sea otters, for instance, are known to carry rocks in skin folds next to their forepaws to use them in area where clams, crabs and abalones are present but rocks aren't. In that sense, the DIK-55 provide evidence for some basic planing depth, though not much more than in some other tool-using animals.

The big question relating to the stone tools here is whether A. afarensis made some or opportunistically used naturally occurring sharp pieces of stone. McPherron et al. (2010) remain agnostic on that one, as well they should given that they've already rocked the boat enough with this discovery and speculating would undermine their case. I also remain undecided on the issue, though I will say that there could be a case for the evidence presented in the paper to indicate that A. afarensis manufactured stone tools. This is based on two lines of observation: 1) there are no large rocks at DIK-55, the largest rocks found there being about 8mm in maximum size; and 2) the bones described in the paper bear both cut marks and percussion marks. Now, cut marks need to be made with a sharp stone edge, something like a flake, or a cobble with at least one flake knocked off. In contrast, percussion marks are made by blunt objects, usually a hammerstone similar to those used to knock flakes off of cobbles or cores. This distinction is usually not given much thought in discussion of human agency on bones because, by and large, if humans have flakes, they have a hammerstone to knap them off with. In fact, even at Gona, the earliest known stone tool assemblage, hammerstones, cores and flakes co-occur (Semaw et al. 1997; Stout et al. 2005).

In this case, however, the distinction is noteworthy because it implies that at least two different implements were brought in to DIK-55 to process the tools. Remember that there are no stones larges than 8mm at this locality, and try as it might, not even a Floresian hobbit would be able to use such small pebbles as tools with much success. It also means that there could be no 'crime of opportunity' in which an australopith just picked up a large rock that was just lying there to smash open a bone. In short, it means that both a blunt stone object (i.e., a hammerstone) and a sharp one must have been transported to DIK-55. Granted, it might simply be that hominins were carrying both unmodified cobbles and naturally occurring sharp pieces of stone with them. But if you understand that whacking a bone with a hammerstone will break it open (and create sharp edges on the bone as a result) and that sharp objects can be helpful in slicing meat off a bone, a parsimonious explanation might be that your lithic technological behavior includes the use of hammerstone to produce stone flakes. This would also make sense from the perspective of lithic technology where percussors and flakes are part of even the simplest toolkits.

Granted, this last bit is speculative, but what is certain is that people will be looking at 3.4-2.6mya deposits with renewed interest and attention in the coming years. What comes out of these investigation should allow us to flesh out the range of possible scenarios brought up by this new discovery from Dikika, which is proving to be an immensely rewarding area from a paleoanthropological standpoint.

In England, ongoing excavations at the Mesolithic site of Star Carr have uncovered the remains of the 10,500 year-old house described as "a round house - a smaller version of iron age round houses - with a circle of timber posts around a sunken circular floor area, which could have been covered by reeds." The structure appears to have been reused and upkept/rebuilt over time (as much as several hundred years), and its discoveries alters the perception of the site's occupants as highly nomadic hunter-gatherers.

Still in Spain, Esquilleu Cave has yielded phytoliths suggesting that the Neanderthals who occupied the site between 53-39,000 years ago arranged mats of grasses around a well-organized central hearth. These mats are taken as further evidence of Neanderthal sleeping structures, which also could have served as "sitting areas during waking hours for the Neanderthals."

Hiya! Back from a little break for Lady Salvatore and I to adjust with life with our firstborn, and back to archaeo/paleo blogging! First off, if you haven't yet seen it, you should clickety-click that mouse right on over to the blognest of the Prancing Papio where you'll find the 98th edition of the Four Stone Hearth, artfully compiled by Raymond. I underscore the FSH connection here since on August 18, 2010, on this very blog, you'll be invited to behold the 99th edition of this fantabulous anthro blog carnival. In fact, not only are you invited to behold all the anthro goodness the web has to offer, you're actively being solicited to contribute a post... I already have a few submissions, but I'd like some more, especially from the cultural and lingusitics side of things... you know you want to, so just get in touch with me to submit a post!